Ab initio studies were made of possible reconstruction elements on Si and Ge(110) surfaces. Using 2 x 2, 3 x 2 and 6 x 2 unit cells, models were optimized which involved buckled atomic chains, dimers, various adatom distributions and interstitial atoms which could exist on the larger Si(110)-(16 x 2) or Ge(110)-(16 x 2)∕c(8 x 10) surface reconstructions. It was shown that adatom reconstructions gained energy. Only the adatom model which seemingly left no dangling bonds could not occur on Si and Ge(110) surfaces. An adatom ↔ rest-atom electron transfer mechanism was more favourable. An adatom-tetramer-interstitial 3 x 2 model also stabilized the Si and Ge surfaces and led to a semiconducting behaviour (for Si). Simulated scanning tunnelling microscopic images of empty states of this reconstruction looked like the pentagon structures observed on Si(110)-(16 x 2). A 6 x 2 reconstruction, with 5-membered ad-clusters, was energetically completely unfavourable although it also reproduced the empty-state pentagon-like scanning tunnelling microscopic images.

Structural Elements on Reconstructed Si and Ge(110) Surfaces. A.A.Stekolnikov, J.Furthmüller, F.Bechstedt: Physical Review B, 2004, 70[4], 045305 (7pp)